The present invention relates to the body of a vehicle such as a railroad car and, more specifically, to the structure of a vehicle body.
FIG. 7 shows a typical structure of a prior-art technique, which is disclosed in Japanese Patent Laid-Open No. 62-189251. As shown in the drawing, a floor 1, which is formed, for example, of aluminum or the like, includes extruded sections 2 and 3 formed by extrusion in the longitudinal direction, i.e., in the direction perpendicular to the plane of FIG. 7. The extruded sections 2 and 3 are welded together to extend in the width direction and have grooves 4, to which underfloor equipment is fastened by means of bolts or the like. Reference numeral 5 indicates a heat insulating material.
A problem with this prior-art structure, in which the floor 1 is formed of the extruded sections 2 and 3, is that its thickness cannot be reduced to a level below a manufacturing limitation. To allow welding operations to be performed, a certain thickness has to be secured, thereby making it difficult to attain a further reduction in weight.